COMNET Introduction

The Commercial Energy Services Network (COMNET)

Download or Print the COMNET Introduction PDF

The Commercial Energy Services Network (COMNET) is a new initiative of RESNET. COMNET extends and supports existing systems for assessing and rating the energy efficiency of commercial and multifamily buildings in the United States.  It consists of a modeling rules component focusing on development of rules and procedures for energy modeling, and is developing a quality assurance component for credentialing and holding accountable energy raters and energy auditors. It is designed to support existing standards and modeling software and to build off existing credentialing systems. By creating a streamlined process with technical rigor, institutional credibility, consistency, and versatility of use across many programs, COMNET will make it more straightforward and cost-effective for building owners to comply with programs and mandates and to reap the benefits of energy efficiency.

What technical and market-based challenges are addressed by COMNET?  

Challenges in Energy Modeling

(1) Unregulated Loads
Currently, no standard process exists to evaluate “unregulated loads” in buildings such as plug loads, commercial refrigeration and vertical transportation. In fact, energy models created for the purposes of code compliance often fail to account for such unregulated loads altogether, resulting in significant discrepancies between the predicted and actual energy use of a building.
(2) Automatic Reference Building Generation
To rate the efficiency of an actual subject building, energy modelers frequently construct energy models of “reference buildings” -- hypothetical buildings identical in many respects to the subject buildings.  The modeler then compares the energy consumption of the subject building to code-compliant baseline and often expresses the result for the subject building as “x% better or worse than code.”  Currently most energy modeling software cannot automatically generate reference buildings.  COMNET will help existing modeling software to add the ability to automatically generate multiple reference buildings corresponding to multiple efficiency standards.  

Market-based Challenges in Building Professional Credentialing

There is increasing demand for the services of building professionals, particularly those who conduct energy audits and create energy models. Therefore, the skills and performance standards for these professionals need to be clearly defined and maintained with the rapidly changing technology related to energy efficiency. Several agencies in the United States offer credentialing for professionals in the energy assessment field, but key issues exist. Existing programs vary greatly in terms of content, rigor and process. And, they lack sufficient quality assurance and mechanisms to hold raters accountable, largely because of resource and staffing limitations.

Developers of energy-efficiency policies, rating systems, and programs in the United States perceive that these existing credentials in themselves are not legal-grade, thus leading to the need to set further requirements, such as stipulations for minimum professional experience and additional review by licensed design professionals. These requirements add cost and complexity, slowing the implementation of energy efficiency initiatives.

COMNET Technical Guidelines & Procedures for Energy Modeling & Rating

The modeling rules component of COMNET focus on developing a set of specific guidelines and procedures that can be incorporated into existing energy modeling software programs. The manual is COMNET’s inaugural product and is now available for incorporation by reference.  It is the first national consensus guidelines on commercial building energy rating processes intended for use in qualifying for federal tax deductions, green building ratings and energy labels.  The manual resulted from extensive public comment and review.

In contrast with the existing system, COMNET will create a unified, streamlined, and rigorous process applicable across multiple programs as illustrated in Figure 1, including for use in:

• Qualifying for federal tax deductions
• Earning building energy labels
• Determining green building ratings 
• Code compliance (in the future)

COMNET provides rules and procedures for calculating predicted energy use of a building based on the building’s physical characteristics. This “asset rating” is determined by modeling building energy consumption under a defined set of standard conditions of occupancy, climate, environment, and use. This modeled consumption is compared against the energy consumption of a hypothetical reference building. COMNET enhances calculation rules for both the subject building and the reference building, with input restrictions and baseline definitions for a comprehensive list of building features and parameters.